Thermal choke, autostart generator system, and method of use thereof

ABSTRACT

A thermal choke, includes (1) a body, comprising a heat conductive material, (2) an electric heater, on or in the body, (3) a temperature sensor, on or in the body, and (4) a fin, in a channel surrounded by the body. The thermal choke is configured to fit between a throttle assembly and a cylinder of a spark ignition engine.

BACKGROUND

Generators for producing electricity are well known and have beencommercially available for many years. These devices typically includean internal combustion engine. They are adapted to provide alternatingcurrent (AC) electricity, through a standard two-prong or three-prongplug receiver, at 120 or 240 volts, and at 50 to 60 Hz; also common isan additional 12 volt DC power port for charging lead acid batteries.Devices which use either gasoline-only or heavy fuels only, such asJP-8, diesel fuel, jet fuel or kerosene, are available.

Gasoline has a low-flashpoint (less than −20° C.) and high autoignitiontemperature (greater than 200° C.). In operation gasoline requires theproper air to fuel ratio and a spark to induce and maintain ignition. Athrottle and/or fuel injector is used to meter the fuel/air mixturewhich is sucked into the cylinders of the engine during operation. Thelow flashpoint and volatility of gasoline allows starting of the sparkignition engine at temperatures below freezing, allowing for operationover a broad range of temperatures typically between −20° C. to 55° C.In order to obtain acceptable efficiency, a compression ratio of 8:1 to12:1 is desirable for a gasoline-only engine, which is low enough toallow for manual pull-starting of the engine and the construction ofsimple lightweight portable engine devices made of aluminum.

Portable gasoline generators have a simple design in order to keep themlight, low cost and durable. Such devices include an engine having acarburetor (which is part of a throttle assembly) for mixing air andfuel, and do not include a fuel injector. A carburetor main jet controlsthe maximum amount of fuel present in the air-fuel mixture exiting thethrottle assembly, and a choke is used to reduce the amount of air inthe air-fuel mixture, for starting the engine.

A small portable generator which could be operated on both gasoline andheavy fuels, such as JP-8, was recently developed (hereinafter referredto as a “flexible fuel generator”): see International ApplicationPublication No. WO 2013/103542. This generator includes an engine, andis similar to a small portable gasoline generator, but has been designedto operate at a temperature range of 120-180° C. The device alsoincludes a start module which delivers a small amount of a low-boilingpoint low-flashpoint fuel to the throttle assembly via the air intake,for starting the engine when using a pull-start. This generator isintended for use in remote field locations, where gasoline may not bereadily available.

A choke valve is sometimes installed in the carburetor of internalcombustion engines. Its purpose is to restrict the flow of air, therebyenriching the fuel-air mixture while starting the engine. Depending onengine design and application, the valve can be activated manually bythe operator of the engine (via a lever or pull handle) or automaticallyby a temperature-sensitive mechanism called an autochoke. Choke valvesare important for naturally aspirated gasoline engines because smalldroplets of gasoline do not evaporate well within a cold engine. Byrestricting the flow of air into the throat of the carburetor, the chokevalve reduces the pressure inside the throat, which causes aproportionally greater amount of fuel to be pushed from the main jetinto the combustion chamber during cold-running operation. Once theengine is warm (from combustion), opening the choke valve restores thecarburetor to normal operation, supplying fuel and air in the correctstoichiometric ratio for clean, efficient combustion. (Fromen.wikipedia.org/wiki/Choke_valve, last updated 26 Oct. 2015.)

Since use of a choke when starting the engine enriches the fuel-airmixture with fuel, undesirable noxious or toxic substances emitted fromthe exhaust of the engine, such as carbon monoxide (CO) from incompletecombustion, hydrocarbons from unburnt fuel, nitrogen oxides (NO_(x))from excessive combustion temperatures, and particulate matter (mostlysoot) are much greater than what is typically emitted by the engineafter the engine has warmed up and the choke valve restored restores thecarburetor to normal operation.

Note that the term “choke” is applied to the carburetor's enrichmentdevice even when it works by a totally different method. Commonly, SUcarburetors have “chokes” that work by lowering the fuel jet to anarrower part of the needle. Some others work by introducing anadditional fuel route to the constant depression chamber. Chokes werenearly universal in automobiles until fuel injection began to supplantcarburetors. Choke valves are still common in other internal-combustionapplications, including most small portable engines, motorcycles, smallpropeller-driven airplanes, riding lawn mowers, and normally aspiratedmarine engines. (From en.wikipedia.org/wiki/Choke_valve, last updated 26Oct. 2015.)

SUMMARY

In a first aspect, the present invention is a thermal choke, comprising(1) a body, comprising a heat conductive material, (2) an electricheater, on or in the body, (3) a temperature sensor, on or in the body,and (4) a fin, in a channel surrounded by the body. The thermal choke isconfigured to fit between a throttle assembly and a cylinder of a sparkignition engine.

In a second aspect, the present invention is an engine, comprising (A) athrottle assembly, (B) a cylinder, fluidly connected to the throttleassembly, (C) a spark plug, in the cylinder, and (D) a thermal choke,between the throttle assembly and the cylinder. The thermal chokecomprises (i) a thermal choke body, comprising a heat conductivematerial, (ii) an electric heater, on or in the body, and (iii) anoptional temperature sensor, on or in the thermal choke body.

In a third aspect, the present invention is a portable flexible fuelgenerator, having an engine, comprising (A) a throttle assembly, (B) acylinder, fluidly connected to the throttle assembly, (C) a spark plug,in the cylinder, (D) a thermal choke, between the throttle assembly andthe cylinder, (E) a primary fuel tank, fluidly connected to thecylinder, (F) an air intake path, fluidly connecting atmosphere to thecylinder, (G) a coolant path, which provide a flow path for coolant tocool the cylinder, and (H) a thermal controller, along the coolant path.The thermal choke comprises (i) a body, comprising a heat conductivematerial, (ii) an electric heater, in the body, and (iii) a temperaturesensor, on or in the thermal choke body.

In a fourth aspect, the present invention is a pull-start activator forpull starting an engine, comprising (I) a mount, (II) an electric motor,attached to the mount, (Ill) a spindle, attached to the motor, and (IV)optionally, a cover on the mount, covering the motor and spindle. Thespindle is configured to connect to a pull start of an engine.

In a fifth aspect, the present invention is an auto-start remotegenerator system, comprising (1) a generator, having an engine, a pullstart for the engine and attachment elements, (2) a pull-startactivator, and (3) an auto-start remote. The generator comprises athermal choke. The auto-start remote comprises (a) a power source,capable of being electrically connected to the generator and thepull-start activator, and (b) a controller, configured to operate thethermal choke and the pull-start activator using power from the powersource, when electrically connected to the generator and the pull-startactivator. The thermal choke comprises (i) a thermal choke body,comprising a heat conductive material, (ii) an electric heater, on or inthe body, and (iii) a temperature sensor, on or in the thermal chokebody.

In a sixth aspect, the present invention is a method of operating anauto-start remote system, comprising providing power to the thermalchoke, until the thermal choke reaches a predetermined temperature, andactivating the electric motor of the pull-start activator, to start theengine of the generator.

In a seventh aspect, the present invention is a computer program productstored on the computer readable medium, for carrying out a method ofoperating an auto-start remote system, the method comprising providingpower to a thermal choke, until the thermal choke reaches apredetermined temperature, and activating the electric motor of thepull-start activator, to start the engine of a generator.

Definitions

Heavy fuels include diesel fuel, diesel 1, diesel 2, kerosene, JP-8,JP-5, F-76, Jet A, Jet A1, F-24, F-34 and bio-diesel. Heavy fuels orgasoline are occasional mixed with a substantial amount of lubricant,such as oil, to form a fuel-lubricant mixture for use in two-strokeengine which do not contain a lubricant. Preferably, Heavy fuels orgasoline is not present as such fuel-lubricant mixtures.

Diesel fuel includes diesel 1, diesel 2, JP-8, JP-5, F-76, Jet A, JetA1, F-24, F-34 and bio-diesel. Diesel fuel does not include kerosene.

Gaseous low-flashpoint fuels include hydrogen, syn gas, natural gas,propane and butane.

Low-boiling point low-flashpoint fuels include diethyl ether andgasoline. These fuels have a boiling point of 15-50° C., and aflashpoint below 0° C.

Fuels include heavy fuels with high flash point and low autoignitiontemperatures, gaseous low-flashpoint fuels, low-boiling pointlow-flashpoint fuels and other high flash point and high autoignitionfuels such as methanol, ethanol and isopropanol. Fuels also includehydrocarbons, such as hexane and heptane. Fuels may contain additives,for example to improve combustion or reduce emissions.

A “portable gasoline generator” is a generator that has an internalcombustion engine and includes a pull start and a carburetor (as part ofa throttle assembly), and uses a spark to ignite fuel-air mixture in theengine, and preferably does not include a battery for starting theengine, and does not include a fuel injector. Such a generator alsoincludes a generator controller, for controlling various electrical andmechanical components of the generator. The compression ratio used inthe engine is greater than 8.0:1, and more preferably 8.1:1 to 12.0:1.Preferably, the engine is air-cooled, has an aluminum cylinder orcylinders, and uses fixed spark plug ignition timing. Preferably, theengine is a 4 cycle, 50 cc engine. Examples of a portable gasolinegenerator include the YAMAHA Inverter EF1000iS, EF2000iS, and EF2000iSH,as well as the HONDA EU1000i, EU2000i and EB2000i.

The term “isothermal” or “isothermally” in the context of the operationof an engine means that the temperature of the cylinder(s) is maintainedsubstantially uniform within a desired temperature range, irrespectiveof engine RPM or ambient external temperature.

A “step-down gas regulator” is a gas regulator that delivers gas at apressure of 0.5 to 1 psi, only supplies the gas under suction. Examplesof such regulators are sold under the brand name “GARRETSON”.

The term “engine” means the internal combustion engine, which includesat least a cylinder, a piston which moves inside the cylinder, a sparkplug, a fuel-air inlet to the cylinder, an exhaust outlet from thecylinder, and a drive shaft which moves with the piston, as well as anoptional carburetor (as part of a throttle assembly), a fixed jet, andpreferably does not include a fuel injector.

The term “running fuel” means a fuel used to run an engine, while theterm “starting fuel” means a fuel used to start an engine.

As used herein, the term module or controller refers to an ApplicationSpecific Integrated Circuit (ASIC), an electronic circuit, a processor(shared, dedicated, or group), circuit boards and/or memory that executeone or more software or firmware programs, a combinational logiccircuit, and/or other suitable components that provide the describedfunctionality. The module or controller may also include regulators andrectifiers for stepping down the voltage available from a power source(such as house hold current or a 24 volt power source) and making itsuitable for operation of the various comments (such a 5 volts DC). Themodule or controller may be used to control the various actions oroutputs based upon various inputs, such as signals from sensors, buttonsand other modules or controllers. Furthermore, when illustrated inschematic form, a single interconnect may be illustrated betweencomponents, but multiple interconnects may be used to provide thedescribed functionality, for example when a controller is connected to adisplay to provide symbols or images to a user. The terms “connected”and “in communication with” are used interchangeably, and include bothdirect and indirect connections. In addition, although multiplecontrollers and/or modules are illustrated and described, a singlecontroller may be able to carry out all such functions with appropriateconnections.

In the following description, 5 volts DC and 24 volts DC are exemplifiedfor operating various electronics and power sources, but many othervoltages and/or AC power could be used, depending on the specificelectronic selected for construction.

A fin means a structure present in the channel of a thermal choke, whichis in contact with the body of the thermal choke and which provide asurface from which fuel may be heated as it passes through the channel.Examples of a fin are a flat, smooth and angled metal piece; a screen;or a round bar extending across the channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures are for illustration of exemplary configurations, and maynot be to scale. The same number in different figures refers to the sameelement, but sometimes different numbers in different figures may referto the same or similar elements.

FIGS. 1 and 2 illustrate a flexible fuel generator having an engineincluding a thermal choke.

FIG. 2A illustrates details of the control panel.

FIG. 3 illustrates a start module of a flexible fuel generator.

FIG. 4 illustrates starting fuel enclosure of a flexible fuel generator.

FIGS. 5 and 6 illustrate the interior of a start module, with andwithout a starting fuel tank, respectively, of a flexible fuelgenerator.

FIGS. 7 and 8 illustrate two configuration of the rear of a flexiblefuel generator, providing details of the thermal controller of aflexible fuel generator.

FIG. 9 is an exploded view of a flexible fuel generator having anengine.

FIG. 10 illustrates a portion of the exploded view of the flexible fuelgenerator shown in FIG. 9.

FIG. 11 is an exploded view of a throttle assembly including a thermalchoke.

FIG. 12 illustrates details of the thermal choke.

FIG. 13 illustrates a schematic diagram of a circuit board andelectrical connections for operating the thermal choke.

FIG. 14 illustrates a system for manual operation of a generator havinga thermal choke.

FIG. 15 illustrates a manual start flowchart showing a method ofoperating the generator using the system for manual operation.

FIG. 16 illustrates a system for automatic operation of a generatorhaving a thermal choke.

FIG. 17 illustrates the systems of FIGS. 14 and 16 in schematic form.

FIG. 18A is an exploded view of a pull-start activator.

FIG. 18B illustrates details of a spindle.

FIG. 18C illustrates a pull-start activator connected to the pull startof a generator.

FIG. 19 illustrates an auto-start remote in schematic form.

FIG. 20 illustrates details of a front panel of the auto-start remote.

FIG. 21 illustrates a method of operating the auto-start remote by auser.

FIG. 22 illustrates a method of operating the generator using theauto-start remote.

FIG. 23 illustrates an anti-diesel module in schematic form.

DETAILED DESCRIPTION

It would be desirable to have an automatic or remote starting system forthe flexible fuel generator. However, the dispensing of the low-boilingpoint low-flashpoint fuel to the throttle assembly via the air intakewhen the running fuel is a heavy fuel, and/or use of a choke forstarting the engine of the generator when the running fuel is gasolineor other similar fuels, requires that a user be present at the generatorto press a button, for example the spray can top of a pressurized can ofether, and/or manually adjust the choke.

The present invention makes use of a thermal choke, which is operatedelectrically, that heats the fuel-air mixture as it exits the throttleassembly and enters the cylinder, avoiding the need to use a low-boilingpoint low-flashpoint fuel as a starting fuel and/or manual operation ofthe choke. Not only does the thermal choke allow the starting of theengine without engaging a manual or automatic choke, but the presence ofa thermal choke avoids the need for a choke to even be present on theengine or generator altogether. Furthermore, the engine may be startedusing the thermal choke, avoiding the need to use as rich of a fuel-airmixture as is typically required to start an engine; this also resultsin significantly reduced start-up emissions of noxious or toxicsubstances. Furthermore, use of alternative fuels, such as heavy fuels,to start the engine is also possible by correct selection of temperaturefor the thermal choke, something simply not possible with a manual orautomatic choke, or even possible with a fuel injector or fuel injectionsystem.

The present invention also optionally makes use of an auto-start systemfor a flexible fuel generator, which includes the thermal choke, apull-start activator for activating the pull start, and an auto-startremote for operating the thermal choke and pull-start activator.Optionally, the flexible fuel generator may include an anti-dieselmodule, which will prevent the engine of the generator from continuingto operate after the spark plug has been grounded, when low octane fuel(such as hexane or heptane) is used as the running fuel.

A thermal choke heats a fuel-air mixture as it exits the throttleassembly, passing through the thermal choke, before it enters thecylinder, and in use is present between the throttle assembly and thecylinder. The thermal choke includes a body and one or more heaters forheating the body. An example of a thermal choke is illustrated in FIG.12.

A generator of the present application may be prepared by adding athermal choke to a portable gasoline generator, such as YAMAHA InverterEF1000iS, EF2000iS, and EF2000iSH, as well as the HONDA EU1000i, EU2000iand EB2000i, or a flexible fuel generator. Preferably, the generator hasan engine that is air-cooled, has an aluminum block and uses fixedtiming. The thermal choke may be used in other spark ignition engines,preferably those that do not have an automatic choke, and preferablythose that do not have fuel injectors, such as those used in lawnmowers, snow blowers and other small portable devices having engines.Furthermore, the pull-start activator, optionally with the auto-startremote could be used with other pull start engine devices, such as lawnmowers and snow blowers. In the following description, a flexible fuelgenerator is used as an exemplary device, for ease of illustration only;it will be recognized that these device could be used in a similarfashion on other machines having pull start engines.

Any fuel may be used as the running fuel, such as heavy fuel, gasoline,alcohol and mixtures thereof, may be used, and any liquid fuel may beused as the running fuel and be present in the primary fuel tank. In avariation, the fuel is diesel fuel. Preferably, the heavy fuel is JP-8.It may be desirable to adjust the size of the jet in the generator tocompensate for the viscosity of the liquid fuel and the anticipatedtemperature of the liquid fuel in the primary fuel tank. It may bedesirable to retard the spark plug ignition timing, as compared to agasoline engine, because of the faster flame speed of heavy fuel. Theprimary fuel tank is fluidly connected to the engine, and deliversliquid fuel to the throttle assembly (which optionally includes acarburetor).

An optional thermal controller adjusts the flow of the coolant throughthe generator. Preferably, the coolant is air. For example, an air fanmay pull air through the generator and over the outside of the cylinder,to cool the cylinder, and then out a cooling air outlet. In thisconfiguration, the thermal controller may be a movable sheet of metal orplastic (a thermal door) which can interrupt the amount of the flow ofair, at any point along the cooling air path. The thermal controller maybe moved to increase or decrease the size of the cooling air outlet. Inan alternative configuration, baffles may be use to increase or decreasethe size of the cooling air outlet or inlet, or along the cooling airpath. In another alternative configuration, the thermal controller maybe a fan, heater or pump coupled to a temperature sensor or thermostat,which increases or decreases the coolant flow to maintain thetemperature within the desired temperature range.

The thermal controller, such as a thermal door, may be used to maintainthe temperature of the cylinder at 120-180° C., preferably 130-175° C.,more preferably 150-170° C., for example 155-165° C. If the temperatureis too low, or too high, the thermal controller can be used to increaseor decrease the flow of coolant. The temperature of the generator ispreferably the temperature of the cylinder, which may be convenientlymeasured at the spark plug using a thermocouple temperature sensor (forexample, a spark plug temperature sensor available from TRAIL TECH).

Optionally, the generator may have full cylinder cooling. In a generatorwith full cylinder cooling, the isothermal operation of the engine maybe maintained. Preferably, the cylinder comprises aluminum (that is, theengine block comprises aluminum), which keeps the generator low inweight, and because of the high thermal conductivity of aluminum,maintains isothermal operation of the engine. Preferably, full cylindercooling comprises cooling the cylinder at the fuel entrance and/or atthe exhaust exit. The HONDA EU1000i and YAMAHA Inverter EF1000iS havefull cylinder cooling. Full cylinder cooling may be achieved in largergenerators (and larger simple engines) by using a heat conductive gasketspacer, such as a ⅜ inch brass gasket spacer. Such a gasket spacer isparticularly useful to provide full cylinder cooling in a YAMAHAInverter EF2000iSH, as well as the HONDA EU2000i and EB2000i, andsimilar 5 kW devices.

Determining if an engine is operating in the isothermal range of120-180° C. and has full cylinder cooling, may be carried out asfollows. The temperature of the engine is measured at the spark plugwhere it is screwed into the engine block, for example by a thermocoupleattached to a washer. The engine is then operated on JP-8 fuel. If theengine does not knock over a period of at least 5 minutes, and thetemperature of the engine is maintained at 120-180° C. during thatperiod (as measured on the engine block at the spark plug), then duringthat time period the engine is operating isothermally at 120-180° C.Furthermore, such operation over the 5 minute period confirms that theengine has full cylinder cooling. In the case of an engine with multiplecylinders, if the temperature at each spark plug is maintained at120-180° C. during the 5 minute period, and knocking does not occur,then during that time period the engine is operating isothermally at120-180° C.; furthermore, such operation over the 5 minute periodconfirms that the engine has full cylinder cooling. An example of fullcylinder cooling is the YAMAHA Inverter EF1000iS, which allows air tocool the cylinder at the fuel entrance and/or at the exhaust exit.

A flexible fuel generator may be prepared by modifying a portablegasoline generator as described in International Application PublicationNo. WO 2013/103542, such as a YAMAHA Inverter EF1000iS, which isair-cooled, has an aluminum block, uses fixed timing, and is a 4 cycle,50 cc engine, having a compression ratio of 8.2:1. The figuresillustrate such a flexible fuel generator, further modified as describedherein. A flexible fuel generator having a thermal choke may also beprepared from a YAMAHA Inverter EF2000iSH, as well as the HONDA EU2000iand EB2000i, and similar 5 kW devices. Optionally, such devices may alsoinclude a carburetor bypass air intake path and a valve, as described inU.S. application Ser. No. 14/493,168 entitled “CARBURETED ENGINE HAVINGAN ADJUSTABLE FUEL TO AIR RATIO” filed Sep. 22, 2014. As illustrated, anoptional start module may be added, which can deliver the low-boilingpoint low-flashpoint fuel, such as diethyl ether, to the back of the airfilter; when the thermal choke is used, such a start module is notneeded. A thermal controller is preferably added to the rear of thegenerator. A temperature display is optionally added, which displays thetemperature at the spark plug. The fixed spark plug ignition timing mayoptionally be retarded, by moving the spark ignition coil clockwise fromits original position. Optionally, a carburetor bypass is added, toprovide a carburetor bypass air intake path. It may be desirable to usehigher quality oil that resists thermal breakdown, such as AMSOIL® SAE10 W-40 synthetic motor oil as the lubricant, or change the lubricantmore often, due to the high temperature operation of the engine whenrunning on heavy fuels and using a thermal controller. In addition itmay be desirable to perform an engine flush treatment to remove carbondeposits from the use of heavy fuels.

In the case of such a modified portable gasoline generator, which hasalso been modified to receive a gaseous low-flashpoint fuel directlyinto the throttle assembly using a step-down regulator, it is possibleto start and operate the generator using only the gaseous low-flashpointfuel, with or without the use of the thermal choke.

FIGS. 1 and 2 illustrate a flexible fuel generator, 10. The generatorincludes a generator housing, 14, which encloses the generator engine(not shown). Exhaust from the generator engine exits through an exhaustoutlet (not shown) and then through an exhaust hose, 12, attached to theexhaust outlet. The generator housing includes a maintenance panel, 16,and a fueling port, 22. Attached to the maintenance door is an optionalstart module, 18. A temperature display, 20, on the generator housingdisplays the internal temperature of the generator engine, as measuredwhere the spark plug attaches to the engine block. An auxiliary display,24, displays other information, such as the length of time the generatorhas been operating. A pull start, 26, for starting the engine, passesthrough the generator housing. A control panel, 28, is present on thegenerator housing. Attachment elements, 29, such as picatinny rails, areoptionally present for attachment of a pull-start activator (not shown),and are configured to receive a mount present on the pull-startactivator.

FIG. 2A illustrates details of the control panel, 28. The control panelincludes a connector, 80, such as a 7-pin connector, and optionally: aconnector cover, 82, a heater status indicator light, 92, an engineon/off switch, 86, a fuel on/off knob, 84, and electrical plugreceivers, 90.

FIG. 3 illustrates an optional start module, 18. The start module isattached to the maintenance panel, 16. The start module includes astarting fuel enclosure, 30, which has a starting fuel button cover, 32,and a starting fuel button access, 34. Also illustrated are enclosurebolts, 36 and 36, which are used to attach the starting fuel enclosureto the maintenance panel. FIG. 4 illustrates an optional starting fuelenclosure, 30. The starting fuel enclosure, 30, has a starting fuelbutton cover, 32, and a starting fuel button access, 34. Alsoillustrated are enclosure bolt holes, 38 and 38, for the enclosurebolts.

FIGS. 5 and 6 illustrate an optional start module with the starting fuelenclosure removed, with and without an optional starting fuel tank,respectively. Shown is the maintenance panel, 16. Attached to the panelare starting fuel tank holders, 40 and 40, for holding a starting fueltank, 48. A starting fuel dispenser, 42, may be attached to the startingfuel tank, to dispense starting fuel. A starting fuel line, 44, attachedto the starting fuel dispenser and passing through the maintenancepanel, transports starting fuel to the air intake path of the generator.Also shown are enclosure bolt tabs, 46 and 46, attached to themaintenance panel, for receiving the enclosure bolts for attaching thestarting fuel enclosure to the maintenance panel of the generatorhousing.

FIGS. 7 and 8 illustrate two configuration of the rear of a flexiblefuel generator, providing details of one type of optional thermalcontroller, a thermal door. Shown in these figures are the generatorhousing, 14, the exhaust port, 58, to which is attached the exhausthose, 12. The thermal door, 50, is slideably attached to the rear of thegenerator housing by clasps, 56 and 56, over the cooling air outlet, 54.In FIG. 7, the thermal door almost completely blocks the cooling airoutlet, while in FIG. 8, the thermal door blocks only a small portion ofthe cooling air outlet.

FIG. 9 is an exploded view of a flexible fuel generator. Here, thegenerator housing, 14 has been split apart to show otherwise hiddenelements. The air filter housing includes a front panel, 60 and a rearpanel, 64, and the air filter, 62, is between these two panels; theseelements are part of the air intake path. Air enters the generator andis pulled through a lower portion of the rear panel to a lower portionof the front panel, and then up along the front panel and through theair filter, and finally out the back of the upper portion of the rearpanel. Also shown in the figure is optional starting fuel line, 44,which has an exit end delivering starting fuel to the back of the airfilter (that is, the side of the air filter facing the rear panel).Although not illustrated in FIG. 9, the entrance end of the startingfuel line is attached to the optional starting fuel dispenser, forming afluid connection between the starting fuel tank and the air intake path.By activation of the starting fuel dispenser, for example by pressingthe top of the starting fuel dispenser, starting fuel is dispensed ontothe back of the air filter. Coolant (in this device, air) flows over thecylinder, 68, including portion of the cylinder at the fuel entrance,63, and at the exhaust exit, 65. Also illustrated in FIG. 9 are thespark plug, 66, the temperature sensor, 67 (which measure thetemperature at the spark plug and is connected to the temperaturedisplay), the throttle assembly, 69, and the primary fuel tank, 74. Notillustrated in the figure are a thermal choke and its associatedelectrical connections, nor a temperature sensor for the fuel bowl andits associated electrical connections. Also not illustrated are circuitboards and electrical connections to the control panel.

FIG. 10 illustrates details of a portion of the exploded view of theflexible fuel generator shown in FIG. 9. Shown are the cylinder, 68, theair fan, 72, and the spark ignition coil, 70. The position of the sparkignition coil controls the timing of the spark plug, because it iscouple to movement of the drive shaft by magnets on the air fan (whichis connected to the drive shaft); as the air fan rotates, the magnetsactuate the spark ignition coil. Since the spark ignition coil iselectrically connected to the spark plug, when the spark ignition coilis actuated, a spark is produced by the spark plug in the cylinder.Furthermore, the air fan pulls air through the generator and over theoutside of the cylinder, to cool the cylinder, and then out the coolingair outlet. As is more clearly illustrated in FIG. 9, the outside of thecylinder includes cooling fins along the full length of the exterior, sothat the cylinder is cooled at both the top and the bottom and thereforehas full cylinder cooling.

FIG. 11 illustrates details of the throttle assembly, 69, as a partiallyexploded view to show detail. Shown are a stepper motor, 238, a fuelbowl, 230, an optional fuel bowl temperature sensor, 240, associatedleads for the sensor, 242, tape, 246, such as self-fusing thermalsilicone self-adhesive tape, for attaching the fuel bowl temperaturesensor to the fuel bowl. Also shown are the thermal choke, 200, andgasket spacers, 232, preferably formed of a heat insulating material,for example plastic such as polyimide gasket spacers. The stepper motorcontrols a butter-fly valve (not illustrated) which acts as thethrottle, limiting the amount of air-fuel mixture which exits thethrottle assembly, passes through the thermal choke and enters thecylinder. The stepper motor is connected to a generator controller (notillustrated), which controls the stepper motor (and hence the throttle)in response to various inputs and signals, and may optionally beconnected to an anti-diesel module (not illustrated). The gasket spacersinsulate the engine block, the fuel bowl and the thermal choke from eachother, and it may be desirable to use 1 to 8 gasket spacers (althoughonly three are illustrated), each having a thickness of, for example 5mils. Additional tape may be applied to the fuel bowl to provideadditional insulation from the heat generated by the thermal choke andthe heat of the engine block. Also illustrated are the drain screwassembly, 234, and the jet screw assembly, 236. Other parts of thethrottle assembly may preferably be replaced with high lubricity or lowwear materials, such as the spring guide, guide for the throttle, andassociated bushing and bearings.

FIG. 12 illustrates details of the thermal choke, 200. As shown, thethermal choke has a body, 250, preferably prepared from a heatconductive material, for example metal (such as 3/16 inch thick brass),with angled fins, 252, for heating the fuel as it passes from thethrottle assembly to the cylinder. Also shown are heaters, 254, such as24 V, 60 W cartridge heaters, inserted into the body for heating thethermal choke, and associated leads, 256, and optional temperaturesensor, 260, for measuring the temperature of the thermal choke, andassociated leads, 258. The heaters and temperature sensor may beinserted into holes in the body, and held in place using, for example,an epoxy adhesive. Although illustrated using 3 heaters, 2 or 4 heatersmay also be used. All parts used for the thermal choke should be ratedto at least 300° C.

Experiments were conducted to determine if other ways to heat the fuel,before it reaches the cylinder, would be as effective as using thethermal choke. For example, by heating the fuel bowl or heating otherparts of the throttle assembly. However, these were not effective, asthey resulted in a fire hazard, thermal expansion of the fuel causingfuel leakage, and/or the melting of the plastic float in the fuel bowl.

In operation, the thermal choke should be heated to 180 to 300° C. whenheavy fuels are to be used as the running fuel. This will allow theengine to be started using the pull start, with a heavy fuel, such asJP-8 or diesel fuel. However, the fuel bowl must not be allowed to gettoo hot, so heating should cease when the fuel bowl reaches atemperature of about 65° C. for JP-8, or 120 to 130° C. for diesel fuel.For gasoline as the running fuel, the thermal choke should be heated to60 to 100° C., and heating should be ceased when the fuel bowl reaches atemperature of about 35° C. For propane as the running fuel, the thermalchoke should be heated to 50 to 100° C. (with no fuel in the fuel bowl,the fuel bowl temperature is not relevant). Use of the thermal chokeavoids the need to use the manual choke when starting the engine. Use ofthe thermal choke also avoids the need to use a starting fuel, such asether from a start module, in order to start a flexible fuel generatorusing a heavy fuel as the running fuel.

FIG. 13 illustrates a schematic diagram of a circuit board, 300, andelectrical connections, present within the generator or flexible fuelgenerator, for operating the thermal choke. A thermal choke controller,302, sends a signal to a heater FET switch, 330, when energized by a 5volt regulator, 324, allowing current from a 24 volt input, 326, toreach the heaters, 304, of the thermal choke. The controller monitorsthe temperature sensor of the thermal choke, 310: the controllerilluminates a red LED, 322, until the temperature of the thermal chokereaches a preset temperature such as at least 230° C. or 240° C. for adwell time, for example 5 to 60 seconds, or 10 to 30 seconds, and thenthe controller stops illuminating the red LED and illuminates a greenLED, 320. These actions cause the heater status indicator of the controlpanel to switch from red to green, letting a user know that the enginemay be started. When the temperature of the thermal choke drops below180° C., the controller will stop illuminating the green LED andilluminate the red LED. Furthermore, the controller also monitors thebowl temperature sensor, 312, and stops the heater FET switch fromallowing current to reach the heaters; this prevents overheating of thefuel bowl, which could cause the plastic float in the fuel bowl to melt,or leakage of fuel from the fuel bowl due to the thermal expansion ofthe fuel. The controller is powered by the 5 volt regulator, 324, whichitself receives power from the 24 volt input. An optional currentsensor, 328, may be used to determine if a heater in the thermal chokeis broken. Optionally, a communication link, 308, to a controller of anauto-start remote (also referred to as an auto-start remote kit, orASRK; not illustrated) and allows control of the controller, 302, by theauto-start remote, and also provides temperature sensor information andother status information to the auto-start remote controller. Anoptional on board temperature sensor, 316, allows the controller todetermine if the circuit board, 300, is over heating and stop the flowof current to the heater FET switch. An optional debug connector, 318,allows for programming, monitoring and/or reprogramming of thecontroller, 302. As illustrated are an optional anti-diesel module, 306,allowing the controller to send a signal to stop operation of the engineby activating the anti-diesel module, and an RMP input, 314, whichmonitors current in the spark plug circuit, allowing the thermal chokecontroller to determine if the engine is running (and allows thecontroller to communicate though the communication link, 308, to theauto-start remote to provide the status of the engine). The 24 voltinput, 326, the communication link, 308, and the debug connector, 318,all operate through one or more pins of a connector (such as a 7-pinconnector) present on the control panel illustrated in FIG. 2A.

It is also possible to operate the thermal choke by simply applying anappropriate current and voltage to the heaters of the thermal choke fora period of time sufficient to bring the temperature of the thermalchoke up to a desired temperature (such 180 to 300° C.). This simple wayof operating the thermal choke is less desirable, as over heating andassociated problem could result.

FIG. 14 illustrates a system for manual operation of a generator, 10(illustrated with an optional exhaust hose, 12), having a thermal choke.The system includes a 24 volt power source, 350 (such as 2 lead acidbatteries connect in series, or a lithium ion battery), connected to thegenerator, 10, through a cable, 352. The cable may be, for example, a7-pin connector cable.

FIG. 15 illustrates a method of operating the generator using the systemfor manual operation; some of these steps are programmed into thecontroller (shown in FIG. 13) while others are carried out by a user.First, the 24 volt power source is connected to the generator, at 600.This causes the red LED to illuminate and begins heating of the thermalchoke to a preset temperature (such as 230° C.), at 602. Once the presettemperature is reach, a dwell time (such as 30 seconds) is allowed topass, at 604, and then the illumination of the red LED is stopped, andthe green LED is illuminated, at 606. The user may then attempt to startthe engine of the generator by pulling the pull start one, two or a fewtimes, at 608. The user then determines if the engine has started (forexample, by the sound or vibrations of the generator), at 610. If theengine is not running, then the user should wait for a period of time soas to avoid flooding the engine with fuel, for example 5 minutes, at612, and then may return to starting the engine by pulling the pullstart, at 608. If the engine does start, then the user should wait for aperiod of time (for example, 30 seconds), at 614, and disconnect the 24volt power source, at 616, which will end illumination of the green LED.If several cycles of attempting to start the engine are unsuccessful,when the wait step at 612 is reached, the user should stop trying tostart the engine and disconnect the 24 volt power source, at 616.

FIG. 16 illustrates a system for automatic operation of a generator, 10(illustrated with an optional exhaust hose, 12), having a thermal choke.The system includes an auto-start remote (also referred to as anauto-start remote kit, or ASRK) 104, connected to the generator, 10,through a cable, 110, such as a 7-pin connector cable. The system alsoincludes a pull-start activator, 102, attached to the generator, 10. Theauto-start remote, 104, is also connected to the pull-start activator,102 (more specifically, to the motor (not illustrated) of the pull-startactivator), by a cable, 108, such as a 7-pin connector cable. Alsoillustrated is an optional auxiliary fuel tank, 354, fluidly connectedto the fuel inlet of the generator, 10, by an auxiliary fuel tanksiphon, 356, which will supply additional fuel to the generator as it isused up during generator operation. The optional auxiliary fuel tank mayalso be used with the system illustrated in FIG. 14.

FIG. 17 illustrates the systems of FIGS. 14 and 16 in schematic form,showing connections between various elements, which may be electrical,physical or fluid connections, depending on the nature of the connectedelements. The generator, 100, includes the thermal choke controller, 120(shown in FIG. 13), thermal choke, 118, throttle assembly (optionallyincluding a carburetor), 126, optional anti-diesel module, 116, theengine, 122, and the control panel, 124. The control panel includeselectrical plug receivers, 130 and 132, the heater status indicator, 128(which displays light of the green and red LEDs), the connector, 134(such as a 7-pin connector), and ground connection, 114. Alsoillustrated in FIG. 17 are the auto-start remote, 104, connected by acable, 110, to the pull-start activator, 102. Further illustrate are the24 volt power source, 106, and cable, 112, which may be used for manualoperation when the auto-start remote and pull-start activator are notused.

FIG. 18A is an exploded view of the pull-start activator, 102. Thepull-start activator includes an optional cover, 400, attached to amount, 406, which together enclose a motor, 402 (such as a 180 watt, 24volt, motor), attached to a spindle, 404. Also connected to the motorand passing through the outside of the cover is a connector, 412, forsupplying power to the motor. As illustrated, latch supports, 408,together with a latch, 410, are part of the mount, allowing mounting ofthe pull-start activator to the outside of the generator usingattachment elements (not shown; illustrated in FIG. 2). Other types ofattachment elements and mounts, each configured to work together, suchas hooks and eyelets, or clips and belts, could be used. Also shown arevarious washers, 414 and 416, and bolts, 417 and 418, for attachingparts of the pull-start activator together (not all the washers andbolts are numbered in the figure).

FIG. 18B illustrates details of the spindle, 404. The spindle is used toattach the pull start (not shown; illustrated in FIG. 2) to the motor,so that the motor may pull the pull start and start the motor. Thespindle includes a body, 428, having a spindle tail, 420, for attachingthe spindle to the motor, and a spindle head, 422, with a notch, 426,for holding the cable and handle of the pull start to the spindle. Thespindle also has a hollow axis, 424, which provides space for attachmentto the motor and parts of the pull start handle. In a variation, thespindle may have a hook, instead of a notch, for attaching the pullstart to the handle.

FIG. 18C illustrates a pull-start activator, 102, connected to the pullstart, 26, of a generator, 10 (only partially shown). The pull start,26, is attached to the spindle, 404, with the cable, 94, threadedthrough the notch of the spindle. When the motor of the pull-startactivator is energized, the cable will wind around the spindle quickly,mimicking the force and speed of a user pulling the pull start, in orderto start the engine. Also illustrated is a portion of the control panel,28, of the generator, and the attachment elements, 29. Other parts ofthe pull-start activator illustrated are the cover, 400, the mount, 406,including the latch supports, 408 and 408, and the latch, 410. Duringuse, the pull-start activator is attached to the generator via theattachment rails and the latch supports and the latch. Alternatively,the pull-start activator could be fixed in location by attachment to awall or a floor, to hold it in place when used.

FIG. 19 illustrates the auto-start remote, 104, in schematic form. Theauto-start remote includes a controller, 450, connected to an optionalfront panel, 458. The controller is also connected to a 24 volt powersource, 452, such as a pair of lead-acid batteries or lithium ionbatteries. The controller will include a 5 volt regulator (notillustrated) for powering other parts of the controller using the 24volt power source. A relay, 456, is switch on when the controlleractivates the pull-start activator (not illustrated), supplying powerfrom the 24 volt power source to the motor of the pull-start activator,through a connector, 457. An optional battery charger, 454, is used tocharge the 24 volt power source when supplied with household current(such as 110 volt, 60 Hz electricity). The controller also may beconnected to the generator through a connector, 459, to communicate withthe controller of the thermal choke (not illustrated) and supply powerto the heaters of the thermal choke.

FIG. 20 illustrates details of the optional front panel, 458, of theauto-start remote, which is connected (in schematic illustration) to theauto-start remote controller, 450, of the auto-start remote, which is inturn connected to a wireless remote control signal detector, 461. Thefront panel includes a display, 460, for providing information to auser, and display menu selection buttons, 466, allowing a user to selectwhat information is provided on the display. Also included are a startbutton, 468, for initiating a program to start the generator using theauto-start remote, and a stop button, 470, to stop operation of thegenerator. Further included are an AC indicator light, 462, forindicating to a user when AC power is being delivered to the auto-startremote, and an AC circuit breaker button, 464, for resetting an ACcircuit breaker after a short circuit has occurred. Lastly, alsoillustrated are a power on-off button, 474, for turning on theauto-start remote, a local/wireless switch, 476, for selecting betweenauto-start remote starting of the generator by use of the start button,468 (local), or a wireless remote control, 463 (wireless), and aconnector, 472, such as a UBS connector, for programming andcommunicating with the auto-start remote controller, 450. The wirelessremote control is capable of sending a wireless communication to thewireless remote control signal detector, for starting and/or stoppingthe auto-start remote and the generator.

FIG. 21 illustrates a method of operating the auto-start remote by auser. The user turns on the power to the auto-start remote, at 650.Next, the user checks the status of the charge of the power source (suchas batteries), at 652, for example by selecting display of thisinformation using the display menu selection buttons. If the powersource is not properly charged or connected, then the use should stopand recharge the power source or connect the power source, at 654. Ifthe power source is properly charged or connected, then the user mayselect wireless mode or local mode, using the local/wireless switch. Ifthe auto-start remote is in the local mode, then the user may initiatestarting of the generator by pressing the start button, at 656, and thenthe auto-start remote will begin operation of the auto-start program, at660. Alternatively, if the auto-start remote is in the wireless mode,then the user may initiate starting of the generator by using thewireless remote control, at 658, and then the auto-start remote willbegin operation of the auto-start program, at 660.

FIG. 22 illustrates a method of operating the generator using theauto-start remote; these steps are programmed into the controller of theauto-start remote. The auto-start remote provides power to the thermalchoke, and when the preselected temperature is reached (for example,230° C.) it is maintained for a preselected period of time (for example10 to 30 seconds), at 670. Next, the auto-start remote will activate themotor of the pull-start activator, for example for 0.8 seconds, at 672.The auto-start remote then determines if the engine has started, forexample by having received such a communication from the RPM input ofthe thermal choke controller, at 674. If the engine has started, thenthe auto-start remote will stop the program, at 676. Alternatively, ifthe engine has not started, then the auto-start remote will return toactivating the motor of the pull-start activator, at 672. If, after forexample 4 times activating the motor of the pull-start activator theengine has not started, the auto-start remote provides power to thethermal choke, and when the preselected temperature is again reached(for example, 230° C.) it is again maintained for a preselected periodof time (for example 10 to 30 seconds), at 678. Next, the auto-startremote will again activate the motor of the pull-start activator, forexample for 0.8 seconds, at 680. The auto-start remote then determinesif the engine has started, for example by having received such acommunication from the RPM input of the thermal choke controller, at682. If the engine has started, then the auto-start remote will stop theprogram, at 684. Alternatively, if the engine has not started, then theauto-start remote will provide an error message to the user via thedisplay, at 686.

When an unmodified portable gasoline generator, operating on gasoline,is stopped using a stop button, the spark plug circuit is grounded,preventing sparking spark plug and combustion of the gasoline.Furthermore, the generator controller causes the stepper motor to openthe throttle, preparing the engine for its next use. However, when heavyfuel is used in a flexible fuel generator, the engine may continue torun for a period of time even when the spark plug circuit is grounded,because the heavy fuel may continue to combusted by compressionignition; to immediately cease operation of the engine it is necessaryto prevent further supply of the fuel-air mixture to the cylinder. Thismay be done by adding an anti-diesel module to the generator, to closethe throttle for a period of time, and then when the engine has ceasedoperating, re-opening the throttle to prepare the engine for its nextuse.

FIG. 23 illustrates an optional anti-diesel module, 116, for preventingthe engine from continuing to operate after the engine has been stop bygrounding the spark plug, when heavy fuels are used in a flexible fuelgenerator. The anti-diesel module includes an anti-diesel controller,500, connected to a pulse detector, 502, for detecting the pulsingelectrical signal present in the spark plug circuit, 512, and a chargebank, 504, which may be a capacitor for providing an electrical supplyto the anti-diesel controller to operate a relay, 506. The pulsedetector and the anti-diesel controller are connected to a 5 voltregulator, 514, for supplying power to operate the pulse detector and/orthe anti-diesel controller, while the charge bank is connected to a 24volt power supply, 516, optionally through a connector (notillustrated). The generator includes a generator controller, 508, whichoperates the stepper motor, 510, of the throttle assembly (through therelay, 506), controlling the throttle of the engine. The anti-dieselcontroller receives a communication from a device, 518, such as anothercontroller (for example, the thermal choke controller or the auto-startremote controller), indicating that the engine is to be stopped. Theanti-diesel controller then switches the relay, 506. This reverses thenormal effect of the generator controller, 508, causing the steppermotor, 510, to close the throttle. When the pulse detector determinesthat the engine has been stopped by the lack of pulses in the spark plugcircuit, it communicates with the anti-diesel controller, to switch therelay back and causing the generator controller, 508, to cause thestepper motor to open the throttle. The pulse detector can be, forexample, a simple wire coil around any part of the spark plug circuit,detecting the spark plug operation by induction.

What is claimed is:
 1. An engine, comprising: (A) a throttle assembly,(B) a cylinder, fluidly connected to the throttle assembly, (C) a sparkplug, in the cylinder, and (D) a thermal choke, between the throttleassembly and the cylinder, (E) a gasket spacer comprising a heatinsulating material, between the throttle assembly and the thermalchoke, and (F) a gasket spacer comprising a heat insulating material,between the cylinder and the thermal choke, wherein the throttleassembly comprises: (I) a fuel bowl, (II) a temperature sensor, on thefuel bowl, and (III) a carburetor, the thermal choke comprises (i) athermal choke body, comprising a heat conductive material, (ii) aplurality of electric heaters on or in the thermal choke body, (iii) atemperature sensor, on or in the thermal choke body, and (iv) aplurality of fins, in a channel surrounded by the thermal choke body,and the heat conductive material comprises metal.
 2. The engine of claim1, wherein the heat conductive material comprises brass.
 3. A method ofgenerating electricity, wherein the electricity is generated using theengine of claim
 2. 4. The engine of claim 1, further comprising: (G) aprimary fuel tank, fluidly connected to the cylinder, (H) an air intakepath, fluidly connecting atmosphere to the cylinder, and (I) a coolantpath, which provides a flow path for coolant to cool the cylinder.
 5. Amethod of reducing start-up emissions from an engine, comprising:providing the engine of claim 1; supplying electricity to the thermalchoke to heat the thermal choke; and starting the engine.
 6. The methodof claim 5, wherein the engine is started with a heavy fuel.
 7. Themethod of claim 5, wherein the engine is started with JP-8.
 8. A methodof generating electricity, wherein the electricity is generated usingthe engine of claim
 1. 9. A method of generating electricity, whereinthe electricity is generated using the engine of claim 1 and the engineis started with a heavy fuel.
 10. A method of generating electricity,wherein the electricity is generated using the engine of claim 1 and theengine is started with JP-8.